In a message dated 97-11-04 06:01:34 EST, you write:
<<
Thanks to Roger Bolick, I have an A-type O/D on my workbench, in
unknown condition. He bought it from Andy Mace a while back. He also
provided an early TR6 O/D trans "core" that had been left out in the
rain without a top cover. The only thing close to being usable is the
o/d mainshaft. The tight tolerances kept most surfaces protected
except the splines for the O/D hook-up and the surface where the caged
bearings ride inside the input shaft. I think I can get away with shot
blasting the splines, but the bearing surface needs to be turned
undersize. Memory tells me that the input shafts on TR6's switched to
a smaller size surface in later years, with a new input shaft and caged
bearing. Is this true, and can I use that input shaft/bearing if I
have the mainshaft machined to fit? I also have a variety of trans
parts from TR3 through late TR6. Can I use the late "steel" bushings
in the earlier boxes? Is there a "hot setup" of gears mixed between the
various ranges is best for a road racer?
TIA
Bob Kramer, Austin TX
Bob-
Wow...talk about a bag-o-snakes...
The thing I love about these type of questions is that they actually "beg"
for OPINIONS....
So here goes...
First thought, be very careful of 250/early 6 boxes. Triumph changed the
angle of the gears there for awhile (somewhere I have the gearbox numbers
involved). What they did was change the angle to decrease the noise
ratio...didn't seem to make a difference so they went back to the original
angle. The angle I'm talkin about is the actaul angle of the teeth on each
gear, again I have the actual angle changes somewhere, but am not at home to
check it out. The difference is quite noticeable if you put two similar gears
next to each other. As I recall they went from something like 22 degrees to
37 degrees, and then back to 22. Obviously none of theses parts are
interchangeable !
The next thing about boxes of that vintage, is that they were NOT all drilled
for the passage between the box and the overdrive unit that allowed oil to
circulate between the two. Without the oil tranfer hole (just to the right of
the layshaft at the rear of the main case) no oil will get into the od unit
and of course you'll hate yourself later.
The mainshaft should work ok if you are putting it into a box with synchros
on all 4 gears (it'll be too long on for a box with only 3 synchros). The
problem with the size of the front of the late 3rd motion shaft is actually
to your favor. The late box used a larger diameter bearing than the earlier
box so you can cut it down to fit your existing bearing size in the 1st
motion shaft (I think there are 4 different sizes of this "snout" on the end
of the 3rd motion shaft if you include the early bronze bushed "bearing"),
but, you'll have to re-harden the end if you cut it down.
Steel vs bronze/brass ...no sweat use either, just don't mix any of the
bushings...all or none.
Always shifty...and always Opinionated...
Nick in Nor Cal
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